Theorem bj-2alim

Description: Closed form of 2alimi . (Contributed by BJ, 6-May-2019)

	Ref	Expression
Assertion	bj-2alim	$$⊢\forall x\forall y\left(\phi \to \psi \right)\to \left(\forall x\forall y\phi \to \forall x\forall y\psi \right)$$

Proof

Step	Hyp	Ref	Expression
1		alim	$$⊢\forall y\left(\phi \to \psi \right)\to \left(\forall y\phi \to \forall y\psi \right)$$
2	1	al2imi	$$⊢\forall x\forall y\left(\phi \to \psi \right)\to \left(\forall x\forall y\phi \to \forall x\forall y\psi \right)$$